Graphic storytelling dates back to caves in France. It's always been around, in everything from graffiti cartoons to tapestries to political cartoons. The comic strip rose up in the late 19th century, becoming one of the key innovations of the newspaper, and eventually, people wanted to read many stories all together instead of one strip at a time. This led to the first collections, and eventually to the invention of comic books. The comic books were often close in tone and content to the comic strip of the days, but would eventually come into something new with the addition of superheroes like Superman in the late 1930s. The comic book, typically monthly, ruled for decades, telling a long, unified story through a series of arcs, sometimes rebooting, sometimes running as a single reality. Even as the mainstream of the fine arts world started taking them seriously, comics were still seen as a non-serious enterprise that could only do long-form storytelling.
Until Will Eisner hit on the idea in the 1970s.
Picture novels, and comics omnibus editions, had been around for decades. Bantam released a hybrid of comic book storytelling with traditional prose called Blackmark in 1971, but it was Eisner's A Contract With God that brought the graphic novel, and the term, into regular use. It was the start of comic book storytelling with a new container. While graphic novels often collect portions of on-going series, they are almost always of a single story told within that series, or a completely new story created specifically for the medium. Since a graphic novel is free of the structure of a traditional comic book, it can go further afield, digging into deeper, heavier storylines. It became a popular format for personal storytelling, such as the works of Eisner or Alison Bechdel, and quickly became popular with artists and writers as a way to tell a more limited story. This suited it to genre storytelling in a more adult vein, since in theory, a graphic novel wasn't competing for shelf space with super heroes.
Marvel jumped on the graphic novel in 1982, releasing a series of well-received graphic novels as the Marvel Graphic Novel line. This line of titles often featured mainstream Marvel characters, but also brought new characters out, and even had a title for Elric, Michael Moorcock's legendary hero. DC released the DC Graphic Novel line slightly later, which led to the DC Science Fiction Graphic Novels, which adapted work by top-flight SF writers like George RR Martin, Ray Bradbury, Fred Pohl, and Harlan Ellison. These helped to get the graphic novel into the mainstream.
By the end of the 1980s, graphic novels were being put out by companies both large and small. Smaller houses like Slave Labor Graphics and Fantagraphics, released many excellent graphic novels of all kinds, and DC and Marvel both used the graphic novel format to explore darker sides of characters and storylines.
This list features a look at graphic novels and collections that tell whole stories. Some series that are split across several trade paperback collections are left out, but everything on the list is a single, sometimes massive, book that you can sit down, enjoy cover-to-cover, and come away with an entire story to digest.